The present invention relates to a new and improved construction of a knot hole beam, for instance a warp beam of a loom, for winding up threads, yarn or other filamentary material or the like, comprising a winding tube or cylinder possesssing at its periphery knot holes, each of the knot holes having an insertion bore serving for the insertion of a bundle of tied together thread or yarn ends and at least one knot arresting opening merging thereat and constructed narrower than the insertion bore.
With prior art knot hole beams, such as disclosed in Schweizerische Technische Zeitschrift, dated Mar. 10, 1949, page 161, and U.S. Pat. No. 785,386, there are proposed two knot arresting openings following the insertion bore which, viewed with respect to the insertion bore, extend in the peripheral direction of the winding tube or cylinder or axially parallel to the winding tube axis and merge with the insertion bore, respectively.
With the first-mentioned course of the knot arresting openings in the peripheral direction the bending strength of the winding tube and its moment of resistance against bending in a direction perpendicular to the axis of the winding tube are relatively markedly reduced. In the presence of more intense traction or tension forces, for instance caused by the warp threads of a loom, which threads are let- or wound-off the knot hole beam (warp beam) during operation, rupture of the winding tube or cylinder can result.
In the case of the second-mentioned course of the knot arresting openings axially parallel to the lengthwise axis of the winding tube, it is indeed so that the bending strength is less affected, however, during operation the knots inserted into the knot arresting opening can slide out relatively easy in the direction of the insertion bore.